Electrostatic discharge protection device and method using depletion switch

Abstract

An integrated circuit device for electrostatic discharge protection that includes a semiconductor substrate, a lightly doped region of a first dopant type formed in the substrate, a first diffusion region of the first dopant type formed at least partially in the lightly doped region, a second diffusion region of the first dopant type formed at least partially in the lightly doped region and spaced apart from the first diffusion region, a resistive path defined by the lightly doped region, the first and the second diffusion regions, and a third diffusion region of a second dopant type formed in the lightly doped region, and disposed between and spaced apart from the first and the second diffusion regions, wherein the third diffusion region keeps the resistive path at a low resistive state until a normal operation period occurs.

1 . A method of electrostatic discharge protection, comprising: 
 (a) providing an integrated circuit device including:    (i) a lightly doped region of a first dopant type;    (ii) a first diffusion region of the first dopant type formed at least partially in the lightly doped region;    (iii) a second diffusion region of the first dopant type formed at least partially in the lightly doped region and spaced apart from the first diffusion region;    (iv) a resistive path defined by the lightly doped region, the first and the second diffusion regions; and    (v) a third diffusion region of a second dopant type formed in the lightly doped region, and disposed between and spaced apart from the first and the second diffusion regions, the third diffusion region controlling the resistive state of the resistive path; and (b) keeping the resistive path at a low resistive state until a normal operation period occurs.    
     
     
         2 . The method of  claim 1 , further comprising: 
 (c) changing the resistive path to a high resistive state as the normal operation period occurs.    
     
     
         3 . The method of  claim 1 , further comprising: 
 (c) providing a control circuit coupled to the third diffusion region to induce a depletion region as the normal operation period occurs.    
     
     
         4 . The method of  claim 3 , further comprising: 
 (d) removing the depletion region as an electrostatic discharge event occurs.    
     
     
         5 . A method of electrostatic discharge protection, comprising: 
 (a) forming a resistive path in a semiconductor well of a first dopant type;    (b) forming a diffusion region of a second dopant type in the semiconductor well to control a resistive state of the resistive path; and    (c) keeping the resistive path at a low resistive state until a normal operation period occurs.    
     
     
         6 . The method of  claim 5 , further comprising: 
 (d) changing the resistive path to a high resistive state as the normal operation period occurs.